Apparatus for wireless signaling.



J. L. HOGAN, JR.

APPARATUS FOR WIRELESS SIGNALING.

APPLICATION FILED ESEPT 9, 1910.

1,014,002.. Patented Jan.9,1912

tmirnn sra rns PATENT orrron.

JOHN L. HOGAN, JR., 013 BRANT ROCK, MASSACHUSETTS, ASSIGNOR TO NATIONAL ELECTRIC SIGNALING COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORA- TION OF NEW JERSEY.

APPARATUS FOR WIRELESS SIGNALING.

. Specification of Letters Patent.

Patented Jan. 9,1912.

To all whom it may concern:

Be it known that 1, JOHN L. HOGAN, Jr., a citizen of the United States, residing at Brant Rock, in the State of Massachusetts, have invented certain new and useful Improvements in Apparatus for l/Vireless Signaling, of which the following is a specification.

My invention relates particularly to the tuning of circuits for transmitting energy by electromagnetic waves, and its primary object is to render more eas and accurate the manipulation of the tuning elements.

I have illustrated the invention as applied to several wireless telegraphy circuits in the accompanying drawing, in which- Figure 1 is a diagram representing a simple circuit of a receiving station arranged to employ my invention. Figs. 2 and 3 are alternative forms having certain further advantages which will hereafter be explained, and Fig. 4 is a simplified diagram representing a simple form convenient for explanation of the principles of the invention.

Heretofore the associated electrical circuits employed in wireless telegraphy have been independently tuned by varying the tuning elements such as capacity and inductance, in each circuit separately, whereby to give the several associated circuits the same natural electrical period. The necessity of moving several indicating devices and making several adjustments has introduced errors and also has required considerable skill in the user of the instruments. By my invention I avoid this difficulty, and incidentally make it possible to more delicately adjust the apparatus, as well as reduce the liability of error.

Referring first to the diagram Fig. 4:, it will be understood that when the circuit A, L G, has the same electrical period as, (2". 0., is in resonance with), the circuit L L 6,, the electrical condition is, that the product of the effective capacity multiplied by the effective inductance, is the same in each of the circuits. Otherwise expressed, if we let L stand for inductance, and C for the capacity, as usual, the condition is 1( 1+ 2) 2 ad a) a where L, and C represent the capacity and inductance of the antenna independent of the inductance L,. If new the product (],L,==G L (C being equal to C,) then the above condition in fulfilled, since L is common to both circuits. Therefore if in Fig. 4, after having found the product of the effective capacity and inductance of the antenna circuit independent of L,, we adjust the elements L and C, in the second circuit so that their product has the same value, then by simply varying the element L which is common to both circuits, we may change the electrical period of both circuits simultaneously and similarly without destroying the condition of perfect resonance between them.

In practice I construct the tuning box containing the elements L L and G with leads arranged to connect the antenna and ground in circuit with L,, and use but a single variable pointer or indicator, that is, the slide of the coil represented by L. in this particular figure. Of course, I may thus vary any kind of tuning element so long as it is common to both circuits.

Fig. 1 shows a preferred form of circuits for use of the invention. Neglecting the coils I and J which may or may not be used, and whose use does not change the matter; the antenna circuit A to G includes inductance L and variable capacity C. and this is inductively connected to the resonant circuit including inductance L similar to L and variable capacity C, similar to G in addition to inductances L and L, and capacityQ. The coil L may be usedas the primary of a transformer connecting to another circuit, or to any detector circuit as for example B, C, R, having the receiver R therein. 4

Again supposing the independent inductance and capacity of the antenna to be respectively L and C the condition for resonance here 1s,

Again, and similarly, in Fig. 2 where the capacities C and C in Fig. 1 are replaced by inductances L and L since for resonance, we may equalize C and C and also the sum of L and L with the sum L +L +L and then resonance will result, for some one degree of coupling between the members L and L whenever L,=L,,. However, if L is made equal to L (2'. e., the primary and secondary of the transformer are given equal self-inductances), the condition of resonance between the associated circuits will hold for all degrees of coupling; because the electrical reactions on and between the primary and secondary coils will be equal for all couplings. That is, while the numerical value of L or of L somewhat as the coupling is changed, yet L will remain equal to L for all couplings. Thus in making L numerically equal to L in the construction of any particular instrument, I am not limited to a single value of coupling in the apparatus.

In Fig. 3 representing an interference preventer circuit, the same symbols are used as before to represent capacity and inductance; and here the condition of resonance between circuits X and Y is,-

4 5 04 and if 0 :6 and the sum L -}-L,,-|-L -l-L equals the sum L,+L,+L,, then when we make (3 :0 the condition is fulfilled for any period and circuits X and Y are tuned. Also if 0 :0 and the sum L,+L L =L,+L +L,, and we make 0 2C the circuits Y and Z are tuned. Therefore if we let C 20 and L,+L -FL +L =L L +L +L,=L,+L +L,, then by giving the capacities C C and C, the same value we will have all the three circuits in resonance and balanced. Evidently C C and. C, may be mounted to be similarly and simultaneously varied.

In the operation ofthe arrangement of Fig. 3, one of the switches P or Q as for example switch P, is opened, and the mechanism simultaneously altering condensers C C and C, are varied until maximum signals are heard. Switch P is then closed, so causing all signals to vanish; (since the entire interference preventer has been placed in balance by the previous operation of may vary tuning). Next the value of either 0 or C, is changed slightly, so unbalancing the interference preventer for the desired signals, but leaving it balanced as regards impulsive disturbances. Of course such operation of the interference preventer is familiar in this art, but by the addition to it of the present invention the facility with which it may be handled is increased.

My invention is not limited to any particular embodiment of the tuning elements, but comprises broadly tuning apparatus in which at least one tuning element is common to several circuits, but arranged and adjusted so that the variation of this one element will similarly alter'the period of several circuits while still preserving resonance.

Having thus described my invention and illustrated its use, what I claim is,

1. The combination with several adjustable oscillation circuits, of a tuning device connecting the several circuits and having an adjustable tuning element arranged to equally and simultaneously vary the elec-.

trical periods of the several circuits, substantially as described.

2. The combination with several interdependent resonant circuits of a tuning device having an element common to said circuits and adjusted so that the variation of said element changes equally the electrical periods of all the said circuits atonce and alike. i a

3. The combination of several associated resonant circuits, each of said circuits having a plurality of tuning elements, one of said tuning elements being variable and com mon to all the circuits, and the other tuning elements in the respective circuits being equalized, so that the variation of said common element will equally and simultaneously change the electrical period of all the circuits, substantially as described.

4. A tuning instrument serving to connect two interdependent resonant circuits, the tuning elements in said two circuits being equalized, and having one tuning element common to both circuits and variable, substantially as and for the purpose described.

In testimony whereof I have hereunto signed my name in the presence of the two subscribed witnesses.

DISCLAIMER.

No.1,014,002.+Jo7m L. Hogan, Jra, BrantRock, Mass. APPARATUS FOR WIRE- LESS SIGNALING. Patent dated January 9, 1912. Disclaimer filed March 23, 1915, by Samuel M. Kintner and Halsey M. Barrett, receivers of the assignee, the National Electric Signaling Company.

Enter this disclaimer To that part of the claim in said specification which is in the following words, to wit, claims 1 and 2 of the patent, as follows:

1, The combination with several adjustable oscillation circuits, of a tuning device connecting the several circuits and having an adjustable tuning element 7 arranged to equally and simu taneously vary the electrical periods of the several circuits, substantially as described. i

2. The combination with several interdependent resonant circuits of a tuning device having an element common to said circuits and adjusted so that the variation of said element changes equally the electrical periods of all the said circuits at once and alike.

[Oficz'al Gazette, March 30, 1915.] 

